반복적 관절내 출혈이 관절 활막과 연골 세포의 변화에 미치는 영향

유명철(Myung Chul Yoo),조윤제(Yoon Jae Cho),김강일(Kang Il Kim),전성욱(Sung Wook Chun),소동혁(Dong Hyuk So),조형준(Hyung Jun Cho),양형인(Hyung-In Yang),이상훈(Sang-Hoon Lee),이연아(Yeon-Ahn Lee) 대한정형외과학회 2008 대한정형외과학회지 Vol.43 No.3

목적: 혈액의 관절강내 반복주사 동물 모델을 이용하여, 혈우병성 관절염에서 활막의 변화와 연골 파괴에 대한 병리 기전과 경과 과정을 연구하였다. 대상 및 방법: 뉴질랜드 백색 토끼 수컷 20마리에 18주간 1주 3회씩 귀에서 자가 혈액을 채취하여 우측 슬관절에 1 ㎖를 주사하고, 좌측 슬관절에 생리식염수 1㎖를(대조군) 주사하였다. 11주 후와 18주 후에 양측 슬관절의 X선 촬영을 시행하였고, 활액막과 연골을 채취하여 조직검사를 시행하였다. 활막 세포 배양에서 RT PCR를 이용한 cytokine의 변화를 관찰 하였고, 연골 세포를 추출 배양하여 GAG 및 PGE₂, MMP-1,3 생성을 측정하였다. 결과: 11주째 육안적 변화는 없었으나, 우측 슬관절의 활액막은 조직학적으로 경한 증식반응과 형질세포 및 단핵세포의 활액막내 침착을 보이며 약간의 염증 소견을 나타냈다. 단순 방사선 소견상 특이 소견은 발견되지 않았다. 18주 후에는 육안적으로 우측 슬관절이 좌측에 비하여 부어 있었고, 단순 방사선학적 소견에서는 관절의 퇴행성 변화가 관찰 되었다. 병리학적 소견은 활막의 심한 증식과 염증세포의 침윤이 관찰되었다. 활막의 real-time RT PCR 시행결과 TNF-alpha, IL-1, MMP-1 mRNA 발현이 증가되었다. 연골세포 배양에서 대조군과 비교시 GAG 생성은 감소하고 PGE₂는 증가하였으며 MMP-1과 MMP-3는 변화가 없었다. 결론: 반복적인 관절 내 출혈은 활막세포를 자극하여 활막의 심한 증식과, proinflammatory cytokines의 생성을 증가시키며, 이는 연골 세포의 재생을 억제하고 연골세포의 염증을 증가시켜 연골의 대사기능이 억제되면서 퇴행성 변화를 촉진하여 점차적으로 관절염으로 이행되는 것으로 사료된다. Purpose: We designed this study to demonstrate the pathophysiology of hemophilic arthropathy (HA) by creating an animal model for determining the effect of repeated intraarticular bleeding in the synovium and articular cartilage. Materials and Methods: 20 normal male New Zealand white rabbits were used for this study. We injected 1 ㎖ of autologous blood from the ear vein of the rabbits into the right knee joint three timeds a week for 18 weeks, and we injected 1 ㎖ of normal saline into the left knee joint three times a week for 18 weeks as a control group. We examined the pathologic changes by microscopy and plain X-ray, and we determined the mRNA expression of proinflammatory cytokines in the synovium of the HA by performing real time RT-PCR at the 11<SUP>th</SUP> week and 18<SUP>th</SUP> week after starting blood-injection. We also examined the GAG and the PGE2 production in cultured chondrocytes that were extracted from the HA knees. Results: At the 11<SUP>th</SUP> week, after blood injection there were no remarkable gross changes in the HA knees and the control knee joints. At the 18<SUP>th</SUP> weeks, the experimental knee joints (HA knees) showed grossly swelling and degenerative changes by X-ray. The infiltration of inflammatory cells and the synovial proliferation in the HA knee joints were compared with that in the control knee joints by microscopic examination. The expressions of the mRNA of TNF-alpha, IL-1, MMP-1 and MMP-3 in the HA synovium were increased, as determined by real time RT-PCR, as compared with that in the control knee. In the cultured chondrocytes, the GAG production was decreased and the PGE2 was increased, but the MMP-1 and MMP-3 were not changed, as determined by ELISA. Conclusion: Our results showed that the GAG production of chondrocytes of the HA knees was decreased and there was increased PGE2, so that the cartilage degeneration by intra-articular bleeding was caused by the decreased metabolism of chondrocytes rather than by increased catabolism of the chondrocytes. We suggest that HA was associated with synovitis and cartilage degeneration, but decreased cartilage metabolism was the major mechanism of HA.

갑상선 분화암 환자의 경과 관찰에서 수술전·후 혈청 갑상선글로불린 측정의 유용성

이성진,원종철,김하영,한정희,이은주,김상욱,류진숙,문대혁,홍석준,안일민 대한내분비학회 2000 Endocrinology and metabolism Vol.15 No.4·5

Design Problems in a Part with Overhang Feature for SLM Process

Il Hyuk Ahn(안일현) 한국소성가공학회 2016 금형가공 심포지엄 Vol.2016 No.8

Quality Control of 3D Printed Parts in Selective Laser Melting Process

( Il Hyuk Ahn ),( Seung Ki Moon ),( Jung Sang Yoo ),( Hyung Sool Oh ) 한국품질경영학회 2015 한국품질경영학회 학술대회 Vol.2015 No.2

Purpose: According to increase the needs of 3D printing technologies in various industries, the Selective Laser Melting (SLM) process technology allows us to produce metallic parts for high performance products using powder materials and laser power. High quality part and product demands are an important issue in 3D printed industries due to the layer-wise nature of additive manufacturing process. The objective of this research is to propose a methodology to develop a metric for maximizing the quality of 3D printed parts with circular holes in the SLM process. Methodology/Approach: In this research, we apply an experimental approach to investigate the relationship between tolerance and geometric error to evaluate the accuracy of the 3D printed parts. In the proposed metric, the geometric error is defined as the difference between the inscribed and circumscribed circles in hole. Findings: We can apply the proposed metric to develop a design guideline for improving the quality of 3D printed parts in the SLM process. Research Limitation/implication: The limitation of this paper is on the case study of fabricating 3D printed parts using one material, A1Sil0Mg that is a widely used for aluminum castings. The future work will focus on extend the proposed methodology to various materials and additive manufacturing processes. Originality/Value of paper: In this research, we proposes a metric to maximize the quality of 3D printed parts based on tolerance and geometric error that are allowed designers to assure the accuracy of the fabricated parts by maximizing the performance of the SML process.

Incidence, Prevalence, and Survival of Moyamoya Disease in Korea : A Nationwide, Population-Based Study

Ahn, Il Min,Park, Dong-Hyuk,Hann, Hoo Jae,Kim, Kyoung Hoon,Kim, Hyun Jung,Ahn, Hyeong Sik American Heart Association, Inc. 2014 Stroke Vol.45 No.4

<P><B>Background and Purpose—</B></P><P>There is a scarcity of information on the epidemiology and natural course of moyamoya disease. The aim of this study was to investigate the nationwide epidemiological features of moyamoya disease in Korea, including incidence, prevalence, and survival.</P><P><B>Methods—</B></P><P>We used the data from nationwide, population-based Health Insurance Review and Assessment Service claims database and Rare Intractable Disease registration program, which includes physician-certified diagnoses based on uniform criteria for moyamoya disease from 2007 to 2011. Age-specific incidence and prevalence were calculated, and survival was examined using Kaplan–Meier method.</P><P><B>Results—</B></P><P>The total number of patients with moyamoya disease was 8154 in 2011, with a female-to-male ratio of 1.8. The incidence from 2007 to 2011 was 1.7 to 2.3/10<SUP>5</SUP>, and the prevalence in 2011 was 16.1/10<SUP>5</SUP>. In total, 66.3% of patients aged 0 to 14 years underwent surgery, whereas only 21.5% in the older than 15 years age group underwent surgery. The 1- and 5-year survival rates of adult patients were 96.9% and 92.9%, respectively, and of child patients were 99.6% and 99.3%, respectively.</P><P><B>Conclusions—</B></P><P>The prevalence and incidence presented in this study are higher than those in previous studies. This study demonstrates that the burden of moyamoya disease in Korea is substantial.</P>

원호 가공에 대한 절삭력 모델

안일혁(Il Hyuk Ahn),최우천(Woo Chun Choi) 대한기계학회 2007 대한기계학회 춘추학술대회 Vol.2007 No.5

Circular milling operations are used to enlarge die and cylinder bores, and machine airframe pockets. In this case, cutting force varies as cutting tool position relative to workpiece. This paper presents a mechanistic model of geometric uncut chip thickness by predicting time varying cutter-part intersection as the cutter travels along the circular path. Compared with experimental results, the suggested cutting force model shows a good agreement.

변곡점에서 공작기계의 윤곽오차

안일혁(Il Hyuk Ahn),김성수(Sung Soo Kim),민경석(Kyung Seok Min),최우천(Woo Chun Choi),홍대회(Daehie Hong) Korean Society for Precision Engineering 2003 한국정밀공학회지 Vol.20 No.11

공구날 특이길이의 물리적 적합성 고찰

안일혁(Il-Hyuk Ahn),김익현(Ik-Hyun Kim),황지홍(Jihong Hwang) Korean Society for Precision Engineering 2012 한국정밀공학회지 Vol.29 No.3

The material removal mechanism in machining is significantly affected by the cutting edge geometry. Its effect becomes even more substantial when the depth of cut is relatively small as compared to the characteristic length which represents the shape and size of the cutting edge. Conventionally, radius or focal length has been employed as the characteristic length with the assumption that the shape of cutting edge is round or parabolic. However, in reality, there could be various ways to determine the radius or focal length even for the same tool edge profile, depending on the region to be considered as cutting edge in the measured profile and the constraints to be set in constructing the best fitted circle or parabola. In this regard, the present study proposes various models to determine the characteristic length in terms of radius or focal length. Their physical compatibility are validated by carrying out 2D orthogonal cutting experiments using inserts with a wide range of characteristic length (30 ? 180 μm in terms of radius) and then by investigating the correlation between the characteristic length and the cutting forces. Such validation is based on the common belief that the larger the characteristic length is, the blunter the cutting edge is and the higher the cutting forces are. Interestingly, the results showed that the correlation is higher for the radius or focal length obtained with a constraint that the center of best fitted circle or the focus of the best fitted parabola should be on the bisectional line of the wedge angle of tool.

Optimization of Microencapsulation of Inonotus obliquus Extract Powder by Response Surface Methodology and Its Application into Milk

Ahn, Sung-Il,Chang, Yoon-Hyuk,Kwak, Hea-Soo Korean Society for Food Science of Animal Resource 2010 한국축산식품학회지 Vol.30 No.4

This study was carried out to optimize microencapsulation conditions for Inonotus obliquus extract powder with mediumchain triacylglycerol (MCT) using response surface methodology (RSM), and to determine the possibility of adding encapsulated I. obliquus extract to milk toward improving the functionality of milk. and to investigate the effects of added encapsulated I. obliquus extract on the physicochemical and sensory properties of the product. The microencapsulation efficiency of I. obliquus extract powder was investigated with respect to three variables (ratios of core material to coating material, amounts of water added, and spray pressure) in RSM. The optimal conditions for microencapsulation of I. obliquus extract powder were obtained from the ratio of core material to coating material (2.92:10) and the amount of water added (0.5 mL); the spray pressure had an insignificant effect on the microencapsulation (p<0.05). Adding encapsulated I. obliquus extract into milk did not significantly affect either color (L, a and b values) or thiobarbituric acid (TBA) values. Sensory test revealed that there were significant improvements in brownish, herb flavor, and bitterness scores for encapsulated I. obliquus extract-added milk as compared with those for uncapsulated I. obliquus extract-added milk. Based on the data obtained from the present study, it is concluded that microcapsules of I. obliquus extract powder could be applicable to milk without remarkably adverse effects on physicochemical and sensory properties

Preclinical investigation for developing injectable fiducial markers using a mixture of BaSO4 and biodegradable polymer for proton therapy.

Ahn, Sang Hee,Gil, Moon Soo,Lee, Doo Sung,Han, Youngyih,Park, Hee Chul,Sohn, Jason W,Kim, Hye Yeong,Shin, Eun Hyuk,Yu, Jeong Il,Noh, Jae Myoung,Cho, Jun Sang,Ahn, Sung Hwan,Choi, Doo Ho Published for the American Association of Physicis 2015 Medical physics Vol.42 No.5

<P>The aim of this study is to investigate the use of mixture of BaSO4 and biodegradable polymer as an injectable nonmetallic fiducial marker to reduce artifacts in x-ray images, decrease the absorbed dose distortion in proton therapy, and replace permanent metal markers.</P>